A damping strut in combination with a spring strut utilized as a wheel suspension for a bicycle is known. The damping strut has a hydraulic shock absorber that is a monotube shock absorber filled with a damping fluid. A damping piston is supported in the monotube shock absorber such that it can be displaced longitudinally for displacing the damping fluid. The damping piston has a plurality of damping openings. During retraction and extension of the damping strut, the damping piston is displaced in the monotube shock absorber, and the damping fluid is displaced by the damping piston such that the damping fluid flows through the damping openings. The flow of the damping fluid in the monotube shock absorber, in particular through the damping openings, is lossy, and results in a damping force that counteracts the movement of the damping strut.
Requirements in particular with respect to the strength and the dynamic of the damping force are applied to the damping strut during occurrence of diverse riding situations with the bicycle, wherein a ride with the bicycle with high safety and with high comfort is supposed to be enabled by the requirements. Thus, it is desirable, when, for example, the bicycle is driven over a high curbstone edge or a lower stone, independent of the stroke position of the damping strut being thereby present, the damping force of the shock absorber is in both cases first possibly low and increases smoothly with a slight increase in the following stroke course so that the highest damping force is reached during reaching a maximum of the obstacle, thus still before the maximum amplitude of the stroke excitation by the obstacle. At the beginning, the damping strut can be retracted fast over the obstacle by the described damping force course, whereby the wheel can dodge the obstacle well without transmitting an overly impact from the curbstone edge or the stone to the frame of the bicycle and whereby the wheel is maximally decelerated during reaching the maximum of the obstacle so that further (and therefore harmful) retraction of the wheel caused by the inertia of the unsprung masses is prevented, whereby a contact loss to the road is prevented. The safety as well as the comfort of the rider during riding is therefore increased and the fluctuation of the wheel load of the sprung wheel is reduced, so that the tyre-road contact is increased.
The stroke excitation is defined as the momentum that causes the movement of the damping strut during the influence duration of the momentum, that is, during the excitation duration. The stroke excitation maximum is the maximum stroke height of a theoretical, barely damped damping strut, wherein the maximum stroke height is caused by this momentum influence. The maximum of the obstacle is the maximum height difference of the obstacle in relation to the height level of the road surrounding the obstacle, wherein the maximum height difference has to be overridden by the damping strut during rolling over the obstacle.
The rider of the bicycle generally performs a rhythmic weight shift during pedalling, whereby the bicycle is brought in a rocking movement. When the rider of the bicycle initiates an abrupt braking manoeuver, the nodding momentum thereby acting on the vehicle's center of mass leads to a strong retraction of the damping strut of the front wheel and simultaneously to a strong extension of the damping strut of the rear wheel. Pedalling induced rocking movements and braking induced retraction and extension movements of the damping strut are tendentiously perceived as being disturbing and can even, when having a too large extends, become a safety risk for the rider. It is therefore further desirable that the damping force possibly increases fast and very strong during these undesired shock absorber movements, whereby these stroke excitations are attenuated by the damping strut still before the damping strut can retract far, so that a ride with high comfort and with high safety is enabled.